CVE-2021-37630: Nextcloud Circles

Medium severity, CVSS 6.5. EPSS: 1.2% chance of exploitation in the next 30 days.

Nextcloud Circles is an open source social network built for the nextcloud ecosystem. In affected versions the Nextcloud Circles application allowed any user to join any "Secret Circle" without approval by the Circle owner leaking private information. It is recommended that Nextcloud Circles is upgraded to 0.19.15, 0.20.11 or 0.21.4. There are no workarounds for this issue.

Affected products

• Nextcloud Circles: before 0.19.5 (fixed in 0.19.5); from 0.20.0, before 0.20.11 (fixed in 0.20.11); from 0.21.0, before 0.21.4 (fixed in 0.21.4)

Published 2021-09-07. Last modified 2026-06-17.